1. Field of the Invention
The present invention relates in general to sensor networks. In particular, but not exclusively, the present invention relates to controlling communication between a set of different sensors and an application that processes sensor information.
2. Description of the Prior Art
Currently, the importance of sensors network is increasing strongly. A substantial information gain is expected by the linkage of different locations and/or different physical or geographical measured values. The following are some examples: By combining different aspect angles within the optical sensor technology one receives additionally spatial information and distances; by combining ambient temperature information and measurement of infrared radiation of objects, it is possible to have better identification capabilities; and, by combined local measurement of waving or temperature distributions one can project waves or temperature gradients more exactly.
Frequently sensors of different organizations or different manufacturers for different measured variables and accuracies are available. The problem, however, is that sensors' interconnection to an application is not standardized. Sensors and applications are often interoperable only with large preparation expenses.
Low-priced mass sensors and precision sensors would offer—interoperability presupposed—completely new possibilities for the illustration of the physical reality in information systems. By scattering small, low-priced sensors over large spatial ranges and by seizing data at critical points, monitoring of various environments would be possible. The following are examples of primary areas of such applications: warning and protection from natural catastrophes; military purposes; public security; warning and protection from environmental pollution; goods and passenger transportation; “intelligent” environments (ubiquitous computing); and telematic and geospatial intended purposes.
The current methods for the development of sensor network applications focuses primarily on writing custom applications. These custom applications are constrained by sensor/actuator-specific hardware and/or software technologies. This custom application approach is a sufficient one for closed homogeneous small-to-medium sized sensor networks. In large sized and/or heterogeneous and/or open/variable networks, where multiple types of sensor and actuator hardware and software may be integrated and re-integrated under a single enterprise wide application, this custom application approach is, however, inflexible and highly costly. It brings interface trouble in the development and lengthens the time to market.
Some current initiatives envision that overall application development for sensor networks will be such that application developers will be concerned only about the essence of their application rather than about the infrastructure nuances of sensor networks. One example thereof is the Open Sensor Web Architecture (OSWA). All these initiatives assume either that there exists a standard for sensor cross-linking or that it is possible by means of special middleware to cross-link all sensors. The latter assumption usually means the use of an instance of the specific middleware on the sensor system itself. Currently, there is no widely accepted or used middleware available for sensors. The establishment of industry-wide standards would certainly play a central role in materializing the benefits of sensor networks, but it will take time before any of the proposed standards will be widely deployed. An overall standard for all kinds of sensors will probably not be enforceable. While standards and a common middleware may be adopted in some areas some day, sensor network application development will continue to follow its current costly path, if no alternative emerge in the short run.
There is thus need for an alternative solution for providing sensor networks including different types of sensors.